Dicing-free led fabrication

ABSTRACT

Provided is a method of fabricating a light-emitting diode (LED) device. A wafer is provided. The wafer has a sapphire substrate and a semiconductor layer formed on the sapphire substrate. The semiconductor layer contains a plurality of un-separated LED dies. A photo-sensitive layer is formed over the semiconductor layer. A photolithography process is performed to pattern the photo-sensitive layer into a plurality of patterned portions. The patterned portions are separated by a plurality of openings that are each substantially aligned with one of the LED dies. A metal material is formed in each of the openings. The wafer is radiated in a localized manner such that only portions of the wafer that are substantially aligned with the openings are radiated. The sapphire substrate is removed along with un-radiated portions of the semiconductor layer, thereby separating the plurality of LED dies into individual LED dies.

PRIORITY DATA

The present application is a divisional application of U.S. patentapplication Ser. No. 12/900,663, filed on Oct. 8, 2010, now U.S. Pat.No. 8,912,033 issued Dec. 16, 2014, the disclosure of which is herebyincorporated by reference in its entirety.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth in recent years. Technological advances in IC materials anddesign have produced various types of ICs that serve different purposes.One type of these ICs includes photonic devices, such as light-emittingdiode (LED) devices. The LED devices are typically fabricated on awafer. To package the individual LED devices, the LED wafer istraditionally sliced to separate the sliced pieces of the wafer into LEDdies. However, the slicing process involves the use of mechanical tools,which may be costly. Further, the slicing process may create contaminantparticles on the LED devices, which will limit the yield and performanceof the LED devices. In addition, the mechanically-sliced LED dies mayhave unsmooth edges, which may also adversely impact the LED device'sperformance.

Therefore, while existing methods of fabricating the LED devices havebeen generally adequate for their intended purposes, they have not beenentirely satisfactory in every aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion.

FIG. 1 is a flowchart illustrating a method for fabricating a LED deviceaccording to various aspects of the present disclosure.

FIGS. 2-9 are diagrammatic fragmentary cross-sectional side views of aportion of a wafer containing LED devices at various stages offabrication in accordance with various aspects of the presentdisclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof the invention. Specific examples of components and arrangements aredescribed below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Moreover,the formation of a first feature over or on a second feature in thedescription that follows may include embodiments in which the first andsecond features are formed in direct contact, and may also includeembodiments in which additional features may be formed interposing thefirst and second features, such that the first and second features maynot be in direct contact. Various features may be arbitrarily drawn indifferent scales for the sake of simplicity and clarity.

Illustrated in FIG. 1 is a flowchart of a method 11 for fabricating anLED device according to various aspects of the present disclosure.Referring to FIG. 1, the method 11 begins with block 13 in a substratehaving a semiconductor layer is provided. The substrate may be asapphire substrate. The substrate has opposite first and second sides.The semiconductor layer is formed on the first side of the substrate.The semiconductor layer may include oppositely doped gallium nitrideepi-layers. The method 11 continues with block 15 in which a patternedphotoresist layer is formed over the semiconductor layer. The patternedphotoresist layers have a plurality of openings therein. The method 11continues with block 17 in which each of the openings is filled with aconductive component. The conductive component may be thermally andelectrically conductive and may include a metal. The method 11 continueswith block 19 in which the semiconductor layer is separated into aplurality of LED dies using a localized radiation process. The radiationprocess is performed from the second side of the substrate. Theradiation process includes radiating a plurality of first regions of thesubstrate. Each of the first regions of the substrate is aligned withone of the conductive components.

FIGS. 2 to 9 are diagrammatic fragmentary cross-sectional side views ofa portion of an LED wafer (a wafer containing LED devices) at variousfabrication stages according to embodiments of the method 11 of FIG. 1.The word “wafer” is used herein to refer to the substrate of the waferas well as the various components formed on the wafer. It is understoodthat FIGS. 2 to 9 have been simplified for a better understanding of theinventive concepts of the present disclosure.

Referring to FIG. 2, a substrate 35 is provided. The substrate 35includes a material that is suitable for growing a light-emittingmaterial. Thus, the substrate 35 may also be referred to as a growthsubstrate or a growth wafer. In one embodiment, the substrate 35includes a sapphire material. In other embodiments, the substrate 35 mayinclude silicon carbide, silicon, or another suitable material forgrowing the light-emitting material.

A semiconductor layer 50 is formed on the substrate 35. Thesemiconductor layer 50 includes oppositely doped semiconductor layers,which may form a P/N junction. In an embodiment, the semiconductor layer50 includes a layer of gallium nitride (GaN) material doped with ap-type dopant such as boron (B), and a layer of gallium nitride materialdoped with an n-type dopant such as arsenic (As) or phosphorous (P).

The semiconductor layer 50 may also include a multiple quantum well(MQW) layer that is disposed in between the oppositely doped (p-type andn-type) layers. The MQW layer has alternating (or periodic) layers ofgallium nitride and indium gallium nitride (InGaN). For example, in oneembodiment, the MQW layer may have ten (or any other suitable number)layers of gallium nitride and ten (or any other suitable number) layersof indium gallium nitride, where an indium gallium nitride layer isformed on a gallium nitride layer, and another gallium nitride layer isformed on the indium gallium nitride layer, so on and so forth. For thesake of simplicity, the oppositely doped p-type and n-type layers andthe MQW layer within the semiconductor layer 50 are not specificallyillustrated.

The oppositely doped layers and the MQW layer of the semiconductor layer50 are formed by an epitaxial growth process known in the art. In theepitaxial growth process, the substrate 35 acts as a seed crystal, andthe layers of the semiconductor layer 50 take on a lattice structure andan orientation that are substantially identical to those of thesubstrate 35. After the completion of the epitaxial growth process, aP/N junction (or a P/N diode) is formed by the disposition of the MQWlayer between the oppositely doped p-type and n-type layers.

When an electrical voltage (or electrical charge) is applied to thedoped layers, electrical current flows through the MQW layer. As aresult, the MQW layer emits radiation such as light in an observablespectrum. The color of the light emitted by the MQW layer corresponds tothe wavelength of the light. The wavelength of the light (and hence thecolor of the light) may be tuned by varying the composition andstructure of the materials that make up the MQW layer.

A layer 60 is then formed on the semiconductor layer 50. The layer 60includes a conductive material. In an embodiment, the layer 60 includesa metal material, for example, Aluminum, Silver, combinations thereof,or another suitable metal material. The layer 60 may be formed bychemical vapor deposition (CVD), physical vapor deposition (PVD), e-gun,thermal evaporator, or another suitable technique.

In an embodiment, the layer 60 serves as an Ohmic contact, meaning itscurrent-voltage (I/V) curve is substantially linear and symmetric. Inanother embodiment, the layer 60 serves as a reflective layer, or amirror, to reflect light emitted by light-emitting diode (LED) devicesthat will be formed from the semiconductor layer 50. In yet anotherembodiment, the layer 60 serves as a capped layer to protect thesemiconductor layer 50. In one more embodiment, the layer 60 serves as aseed layer (also referred to as an adhesive layer) for a plating processto be performed later, which will be discussed below. It is understoodthat the layer 60 may serve all the functions/purposes discussed above.Alternatively, a separate layer may be formed to carry out each of thesefunctions/purposes discussed above. For example, the layer 60 may serveas the Ohmic contact layer, another layer may be formed over the layer60 and may serve as the reflective layer, and a capped layer may beformed over the reflective layer, etc.

A photoresist layer 70 is then formed over the layer 60. The photoresistlayer 70 includes a photosensitive material and may be formed by aspin-coating process or another suitable technique.

Referring now to FIG. 3, the photoresist layer 70 is patterned by aphotolithography process, also referred to as a patterning process. Thephotolithography process may include a plurality of masking, exposing,developing, baking, rinsing, and stripping processes, among otherprocesses. As a result of the photolithography process, the photoresistlayer is patterned into a plurality of photoresist components (alsoreferred to as photoresist portions). For the sake of providing anexample, five of such photoresist components 70A, 70B, 70C, 70D, and 70Eare shown in FIG. 3. The photoresist components 70A-70E are each formedto be in (or over) a scribe line (also referred to as a street line)region of the wafer. The scribe line or street line regions are wherethe LED dies are to be physically separated before they are packaged.One reason for forming the photoresist components 70A-70E is to avoidcutting of metal in the fabrication of LED devices. This will bediscussed in more detail below.

The photoresist components 70A-70E are separated by openings 80, 81, 82,and 83. The openings 80-83 each have a lateral dimension (or width) 90.In an embodiment, the width 90 is in a range from about 0.5 mili-meter(mm) to about 2 mm. It is understood that in alternative embodiments,the openings 80-83 may not have equal lateral dimensions.

Referring now to FIG. 4, conductive components (also referred to asconductive portions) 100, 101, 102, and 103 are formed in the openings80, 81, 82, and 83, respectively. In an embodiment, the conductivecomponents 100-103 are formed using an electrochemical plating (ECP)process known in the art. As discussed above, the layer 60 may serve asa seed layer in the ECP process for growing the conductive components100-103 in the openings 80-83. Alternatively, another layer may beformed over the layer 60 to serve as the seed layer for the ECP process.In an embodiment, the conductive components 100-103 each include amaterial that is both thermally conductive and electrically conductive,such as a metal material. The conductive components 100-103 at leastpartially fill the openings 80-83.

Referring to FIG. 5, a glue material (also referred to as an adhesivematerial) 110 is formed over the photoresist components 70A-70E and theconductive components 100-103. In an embodiment, the glue material 110is a material that is activated by an ultra-violet (UV) light, that is,the glue material 110 becomes irreversibly adhesive after being radiatedby a suitable UV light.

Thereafter, a layer 120 is formed over the glue material 110. In anembodiment, the layer 120 includes a light-to-heat conversion material.As such, the layer 120 may also be referred to as a light-to-heatconversion (LTHC) conversion layer. This means that the layer 120 isoperable to absorb radiation waves such as light, and then convert thatradiation to heat.

A substrate 130 is then bonded to the layer 120 using a glass bondingtechnique known in the art. In an embodiment, the substrate 130 includesa glass substrate. The glass material of the substrate 130 is chosen sothat it will let a substantial amount of radiation pass through withoutabsorbing the radiation. In an alternative embodiment, the light-to-heatconversion layer 120 is formed on the glass substrate 130 first, andthen the glass substrate 130 is bonded to the glue material 110 with thelight-to-heat conversion layer being the interface between the gluematerial 110 and the glass substrate 130.

Referring now to FIG. 6, a localized radiation process 140 is performedon the substrate 35. The radiation process 140 is performed from a sideof the substrate 35 opposite to the side of the substrate 35 on whichthe semiconductor layer 50 is formed. In an embodiment, the radiationprocess 140 includes a laser scan process that uses a 248 nanometer (nm)KrF laser. The radiation process 140 is localized in the sense that onlyselected regions of the substrate 35 are exposed to the radiation.Correspondingly, only the regions of the semiconductor layer 50 that arealigned with the selected regions of the substrate 35 are exposed to theradiation.

In an embodiment, the regions of the substrate 35 and the correspondingregions of the semiconductor layer 50 being radiated are eachsubstantially aligned with one of the conductive components 100-103. Forthe sake of clarity, these regions are designated as regions 35A-35D and50A-50D, respectively, wherein the boundaries of these regions are shownas dashed lines within the substrate 35 and the semiconductor layer 50.The remaining regions of the substrate 35 and the semiconductor layer 50are each aligned with one of the photoresist components 70A-70E. Theseremaining regions of the substrate 35 and the semiconductor layer 50 aredesignated as regions 35E-35I and 50E-50I, respectively, for the sake ofclarity.

It is understood that in alternative embodiments, the regions 35A-35Dand 50A-50D may be narrower than the conductive components 100-103.Alternatively stated, the regions 35A-35D and 50A-50D may have smallerlateral dimensions than the lateral dimension 90 of the openings 80-83(shown in FIG. 3), which is also the lateral dimension of the conductivecomponents 50A-50D (since the conductive components 50A-50D fill theopenings 80-83).

The radiation from the radiation process 140 is selected in a manner sothat it mostly passes through the substrate regions 35A-35D and getabsorbed by semiconductor regions 50A-50D. As a result of the radiation,a nitrogen gas is generated and released at the interfaces between thesubstrate and semiconductor regions 35A and 50A, 35B and 50B, 35C and50C, 35D and 50D, respectively. Consequently, the substrate regions35A-35D become separated from the semiconductor regions 50A-50D.Meanwhile, the substrate regions 35E-35I are still attached to thesemiconductor regions 50E-50I, because these regions were not exposed toradiation, and thus no nitrogen gas was released between theirrespective interfaces.

In an alternative embodiment, a dry etching process is performed to etchaway the substrate regions 35E-35I and the semiconductor regions 50E-50Ibefore the radiation process 140 is performed. Thus, openings will beformed in place of the substrate regions 35E-35I and the semiconductorregions 50E-50I. This dry etching process may be carried out in a mannerso that the openings have substantially smooth sidewalls. For the sakeof simplicity, this alternative embodiment is not specificallyillustrated.

Referring now to FIG. 7, the substrate 35 is removed along with thesemiconductor regions 50E-50I using a substrate removal process 150. Thesubstrate removal process 150 may include a lift off process. Thesubstrate 35 can be easily lifted off the semiconductor regions 50A-50D,since the radiation process 140 (shown in FIG. 6) has already separatedthe substrate 35 from the regions 50A-50D through the release ofnitrogen gas. The semiconductor regions 50E-50I can be removed alongwith the substrate 35 because the semiconductor regions 50E-50I stillremain attached to the substrate 35 at the completion of the radiationprocess 140, as discussed above. The substrate 130 provides mechanicalstrength and support during the substrate removal process 150.

In an embodiment, portions of the layer 60 below (and aligned with) thesemiconductor regions 50E-50I also remain attached during the substrateremoval process 150 and are therefore removed together with thesubstrate 35. In an alternative embodiment, these portions of the layer60 below and aligned with the semiconductor regions 50E-50I may beetched away after the substrate removal process 150 is performed. Inaddition, it is understood that in some alternative embodiments, thesubstrate 35 may be removed using a grinding process, achemical-mechanical polishing (CMP) process, or one or more suitableetching processes.

Referring to FIG. 8, contact pads (also referred to as electrodes) 160,161, 162, and 163 may be formed on the semiconductor regions 50A, 50B,50C, and 50D, respectively. The semiconductor regions 50A-50D are mainportions of LED dies and may be referred to as LED dies or LED devices.The contact pads 160-163 may be used to apply electrical voltages to theLED dies 50A-50D.

After the contact pads 160-163 are formed, a substrate removal process170 is then performed to removal the substrate 130. In an embodiment,the substrate removal process 170 includes a laser scan process, inwhich the substrate 130 is radiated by a laser. As discussed above, thematerial of the substrate 130 is selected so that it absorbs a minimalamount of radiation. Therefore, the radiation from the laser scanprocess mostly passes through the substrate 130 without being absorbed,and most of the radiation is actually absorbed by the layer 120.

Also as discussed before, the layer 120 includes a material thatconverts radiation such as light into heat. Thus, the radiation from thelaser scan process is absorbed by the layer 120 and subsequentlytransformed into heat energy. The heat energy causes the substrate 130to become de-coupled from the layer 120. Thus, the substrate 130 may bede-bonded from the layers above using the laser scan process. Inalternative embodiments, the substrate 130 may be de-bonded using achemical treatment process, a peeling off process, or combinationsthereof. The layer 120 may be removed during the removal of thesubstrate 130 or thereafter.

Referring now to FIG. 9, a glue removal process 180 is used to removethe glue material 110. In an embodiment, the glue removal process 180includes a peeling off process, in which the glue material 110 is peeledoff along with the photoresist components 70A-70E. One of the reasonsthat the photoresist components can be peeled off along with the gluematerial 110 is that, the adhesion force between the photoresistcomponents 70A-70E and the glue material 110 is stronger than theadhesion force between the photoresist components 70A-70E and theconductive components 100-103 adjacent to the photoresist components70A-70E.

Meanwhile, the adhesion force between the conductive components 100-103and the glue material 110 is not as strong as the adhesion force betweenthe conductive components 100-103 and the layer 60. Therefore, theconductive components 100-103 will not be peeled off along with the gluematerial 110. Also, although not illustrated for the sake of simplicity,the entire wafer may be transferred to a blue tape (used to carry outfurther processing) before the glue material 110 is removed.

At this stage of fabrication, it can be seen that the LED dies 50A-50Dhave been completely separated from one another, where no mechanicaldicing processes are used to accomplish such separation. It isunderstood that addition processes may be performed to complete thefabrication of each individual LED die. For example, an encapsulantstructure may be formed over each LED die to mold the LED die. Theencapsulant structure may include an organic material such as resin orplastic and may provide sufficient sealing for the LED die to minimizecorrosion concerns. Lenses may also be formed for each LED die, so thatthe light emitted by the LED die may be directed and focused in anintended propagation direction. For the sake of simplicity, theseadditional fabrication processes are not discussed in detail herein.

The embodiments of the present disclosure discussed above haveadvantages over existing methods. It is understood, however, that otherembodiments may offer different advantages, and that no particularadvantage is required for any embodiment. One of the advantages is thatno mechanical dicing processes are used to physically separate the LEDdies. Traditional LED fabrication processes may involve the use ofmechanical saw devices to cut through the scribe line regions, which arealso referred to as street line regions of the LED wafer. This sawingprocess may damage the edges of the LED dies. Moreover, if the LED diesare formed on a metal substrate, the sawing may create metal contaminantparticles, which may substantially degrade the performance and yield ofthe LED devices.

Here, photoresist components (such as 70A-70E) are formed in (or over)the scribe line or street line regions of the LED wafer. The thermallyconductive metal components (such as 100-103) are formed between thescribe line regions—in other words, the conductive metal components areformed directly underneath the LED dies. As such, no cutting of metal isneeded—since these conductive metal components are not formed in thescribe line regions by design. The elimination of metal cutting willincrease yield and improve performance of the LED devices as well asreduce LED fabrication costs.

Also, the sapphire substrate removal process (such as process 150)requires no physical or mechanical cutting, since it is carried outusing a radiation process 140 (shown in FIG. 6). The semiconductorregions (such as 50E-50I) in the scribe line regions can be removedalong with the sapphire substrate 35, which simplifies LED fabricationprocesses. Also, in the embodiment where dry etching is used to formopenings in the scribe line regions, the resulting LED dies have smoothsidewalls, which may also help increase yield and improve performance ofthe LED devices.

Another advantage is that each conductive metal component serves as agood heat sync for the respective LED device. This may be beneficial,especially when the LED devices generate large amounts of heat duringits operation.

An additional advantage is that the photoresist components (such as70A-70E) can be removed during the removal of the glue material 110.Once again, this simplifies the fabrication of the LED devices andtherefore reduces fabrication costs.

One of the broader forms of the present disclosure involves a method.The method includes: providing a substrate having opposite first andsecond sides, wherein the first side has a semiconductor layer formedthereon; forming a photoresist layer over the semiconductor layer;patterning the photoresist layer into a plurality of photoresistcomponents, the photoresist components being separated by openings;filling the openings with a plurality of thermally conductivecomponents; and separating the semiconductor layer into a plurality ofdies using a radiation process that is performed to the substrate fromthe second side, each of the first regions of the substrate beingaligned with one of the conductive components.

Another of the broader forms of the present disclosure involves a methodof LED fabrication. The method includes: providing a wafer having asapphire substrate and a semiconductor layer formed on the sapphiresubstrate, the semiconductor layer containing a plurality ofun-separated LED dies; forming a photo-sensitive layer over thesemiconductor layer; performing a photolithography process to patternthe photo-sensitive layer into a plurality of patterned portions, thepatterned portions being separated by a plurality of openings that areeach substantially aligned with one of the LED dies; forming a metalmaterial in each of the openings; radiating the wafer in a localizedmanner such that only portions of the wafer that are substantiallyaligned with the openings are radiated; and removing the sapphiresubstrate along with un-radiated portions of the semiconductor layer,thereby separating the plurality of LED dies into individual LED dies.

Still another of the broader forms of the present disclosure involves amethod of fabricating an LED device. The method includes: providing asapphire substrate having a semiconductor layer formed thereon; forminga patterned photoresist layer over the semiconductor layer, thephotoresist layer having an opening therein; forming a conductivecomponent in the opening; and radiating a first portion of the sapphiresubstrate with a laser, the first portion of the sapphire substratebeing aligned with the conductive component; wherein: a second portionof the sapphire substrate that is aligned with the patterned photoresistlayer is not radiated; in response to the radiating, the first portionof the sapphire substrate becomes separated from a first portion of thesemiconductor layer therebelow, the first portion of the semiconductorlayer being aligned with the conductive component; and the secondportion of the sapphire substrate remain coupled to a second portion ofthe semiconductor layer therebelow after the radiating, the secondportion of the semiconductor layer being aligned with the patternedphotoresist layer.

The foregoing has outlined features of several embodiments so that thoseskilled in the art may better understand the detailed description thatfollows. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method of fabricating a light-emitting diode(LED) device, comprising: forming a photo-sensitive layer over asapphire substrate having a semiconductor layer formed thereon, whereinthe semiconductor layer includes III-V group compound layers withdifferent types of conductivity, and wherein the photo-sensitive layeris formed over a scribe-line region of the sapphire substrate;patterning the photo-sensitive layer into a plurality of portions thatare separated from one another by a plurality of openings; forming aconductive material in each of the openings; radiating portions of thesapphire substrate and portions of the semiconductor layer formedthereon that are aligned with the openings; and removing the sapphiresubstrate along with un-radiated portions of the semiconductor layer. 2.The method of claim 1, wherein the semiconductor layer includes aplurality of un-separated LEDs.
 3. The method of claim 2, wherein theplurality of openings are vertically aligned with the plurality ofun-separated LEDs, respectively.
 4. The method of claim 2, wherein theremoving of the sapphire substrate along with the un-radiated portionsof the semiconductor layer causes the plurality of LEDs to be separatedinto individual LEDs.
 5. The method of claim 1, further comprising:forming an adhesive layer over the portions of the photo-sensitivelayer; providing a glass substrate with a light-to-heat conversion layerdisposed thereover; and bonding the adhesive layer to the glasssubstrate such that the adhesive layer is in physical contact with thelight-to-heat conversion layer.
 6. The method of claim 5, furthercomprising: applying radiation to the light-to-heat conversion layer togenerate heat; thereafter removing the glass substrate; and peeling offthe adhesive layer such that the portions of the photo-sensitive layeris peeled off along with the adhesive layer.
 7. The method of claim 1,further comprising: before the forming of the photo-sensitive layer,forming a metal layer over the semiconductor layer.
 8. The method ofclaim 1, further comprising: before the radiating, dry etching portionsof the substrate that are aligned with the portions of thephoto-sensitive layer.
 9. A method of fabricating a light-emitting diode(LED) device, comprising: providing a wafer having a sapphire substrateand a semiconductor layer formed on the sapphire substrate, thesemiconductor layer containing a plurality of un-separated LED dies;forming a photo-sensitive layer over the semiconductor layer; performinga photolithography process to pattern the photo-sensitive layer into aplurality of patterned portions, the patterned portions being separatedby a plurality of openings that are each substantially aligned with oneof the LED dies; forming a metal material in each of the openings;radiating the wafer in a localized manner such that only portions of thewafer that are substantially aligned with the openings are radiated; andremoving the sapphire substrate along with un-radiated portions of thesemiconductor layer, thereby separating the plurality of LED dies intoindividual LED dies.
 10. The method of claim 9, wherein: thephotolithography process is carried out in a manner so that each of thepatterned portions of the photo-sensitive layer is aligned with a scribeline region of the wafer.
 11. The method of claim 9, wherein thesemiconductor layer includes oppositely doped gallium nitride layers.12. The method of claim 9, further including: forming a glue materialover the patterned portions of the photo-sensitive layer and the metalportions; forming a light-to-heat conversion layer over a glasssubstrate; and bonding the glass substrate to the glue material in amanner so that the light-to-heat conversion layer comes into contactwith the glue material.
 13. The method of claim 12, further including:radiating the light-to-heat conversion layer to generate heat; removingthe glass substrate in response to the heat; and peeling off the gluematerial, the patterned portions of the photo-sensitive layer beingglued to the glue material and being removed along with the gluematerial.
 14. The method of claim 9, further including: before theforming of the photo-sensitive layer, forming a conductive layer overthe semiconductor layer, the conductive layer serving as one of: anohmic layer, a reflective layer, a capped layer, and a seed layer forthe metal portions.
 15. The method of claim 9, further including: beforethe radiating, performing a dry etching process on portions of the waferthat are substantially aligned with the patterned portions of thephoto-sensitive layer.
 16. A method of fabricating a semiconductordevice, comprising: providing a sapphire substrate having asemiconductor layer formed thereon; forming a patterned photoresistlayer over the semiconductor layer, the photoresist layer having anopening therein; forming a conductive component in the opening; andradiating a first portion of the sapphire substrate with a laser, thefirst portion of the sapphire substrate being aligned with theconductive component; wherein: a second portion of the sapphiresubstrate that is aligned with the patterned photoresist layer is notradiated; in response to the radiating, the first portion of thesapphire substrate becomes separated from a first portion of thesemiconductor layer therebelow, the first portion of the semiconductorlayer being aligned with the conductive component; and the secondportion of the sapphire substrate remains coupled to a second portion ofthe semiconductor layer therebelow after the radiating, the secondportion of the semiconductor layer being aligned with the patternedphotoresist layer.
 17. The method of claim 16, further including, beforethe radiating: forming an adhesive material over the photoresist layerand the conductive component, the adhesive material being activated byan ultra-violet light and being glued to the photoresist layer; forminga light-to-heat conversion layer on a glass substrate; and coupling theglass substrate to the adhesive material, the light-to-heat conversionlayer serving as an interface between the glass substrate and theadhesive material.
 18. The method of claim 17, further including, afterthe radiating: removing the sapphire substrate along with the secondportion of the semiconductor layer that is coupled to the sapphiresubstrate; thereafter removing the glass substrate using a laser scanprocess that generates heat within the light-to-heat conversion layer;and thereafter removing the adhesive material along with the photoresistlayer that is glued thereto.
 19. The method of claim 16, furtherincluding, before the forming the patterned photoresist layer: forming aconductive layer over the semiconductor layer; and wherein: theconductive layer serves as an ohmic contact for the semiconductor layer;and the patterned photoresist layer is formed on the conductive layer.20. The method of claim 16, further including, before the radiating: dryetching an opening that extends through the second portion of thesapphire substrate and the second portion of the semiconductor layer.